ACHE and early-onset autosomal dominant Alzheimer disease: Particularly, lycodine-type alkaloids, which generally characterized by four connected six-membered rings, including a pyridone or pyridine ring, a piperidine ring, and a bicyclo[3.3.1]nonane core [8], are a unique class of compounds and have attracted great interest for their biological activities especially the extraordinary acetylcholinesterase (AChE) inhibition by huperzine A that has a potential of becoming a therapeutic agent for the treatment of Alzheimer’s disease [2, 9].